Foam-inhibited aqueous oil emulsions



. bustion, and the like.

United States Patent FOAM-INHIBITED AQUEOUS OIL EMULSIONS William 1. Gilbert, Oakmont, and Arthur C. Whitaker,

Pittsburgh, Pa., assignors to Gulf Research 8: Development Company, Pittsburgh, Pa., a corporation of Delaware N0 Drawing. Filed Oct. 21, 1958, Ser. No. 768,563

3 Claims. (Cl. 252-334) This invention relates to the prevention of foaming of hydrocarbon oils and oil compositions, particularly mineral oils and aqueous emulsions thereof.

Mineral oils and their aqueous emulsions tend to foam or froth when agitated in the presence of gases or vapors, such as air, steam, oil vapor, products of com- The amount of foam or froth varies with the conditions under which the oil or oil compositions are agitated, as well as with the characteristics of the particular composition. Under some conditions, the volume of foam or froth produced is many times that of the original composition, and even with mild agitation substantial amounts of foam are produced in many oil compositions. In preparing and using such oils and oil compositions commercially, they are subjected to agitation under a wide range of conditions and frequently undesirable amounts of foam or froth are produced.

Various means of combatting such foaming of oils or oil compositions have been proposed. For instance, mechanical devices have been prepared for destroying or breaking foam as it is formed. Usually such devices have been cumbersome or inetficient, or both, and they are not generally used commercially. Likewise, the incorporation of certain oil-soluble compounds in the oil has been proposed as a means for preventing foaming of oils, such compounds being called anti-foam agents." While some of the prior agents have effectively reduced foaming of mineral oils, the agents have been less efiective or inefi'ective in cutting liquid emulsions obtained when a so called soluble oil" is emulsified with water. Some agents have efiectively reduced foaming of aqueous oil emulsions but they have been less efiective in mineral oils. Some of the prior anti-foam agents have efiectively reduced foaming of oils and oil compositions maintained at room temperature, i.e., about 70 to about 80 F., but the agents have been less efiective in oils maintained at an elevated temperature. Some of the prior agents have been found even to increase the amount of foam formed in mineral oils maintained at about 200 F., particularly in the'heavier oils, i.e., oils having a viscosity above about 100 SUS at 100 F.

It is important to provide an oil or oil composition which is markedly resistant to foaming at an elevated temperature as well as at room temperature. For example, in the lubrication of internal combustion engines such as automotive, aviation, diesel and like engines, the temperature of the oil in the crankcase during engine operation is usually within the range of about 100 to about 225 F. In lubricating such engines, appreciable foaming of the oil seriously interferes with effective lubrication. Likewise, in the lubrication of metal working operations, high temperatures are encountered. In lubricating such metal working operations, appreciable foaming of the oil composition not only interfere! with efiective lubrication of the cutting operation but also with the removal of heat evolved in the operation and with the washing away of the metal chips which are formed. By the present invention, the foaming encountered in lubricating internal combustion engines with a mineral oil as well as that encountered in lubricating metal working operations with a cutting liquid composed of water and a soluble cutting oil is efiectively reduced.

We have discovered that the. foaming of hydrocarbon oils, particulary mineral oils and aqueous emulsions containing them, can be efiectively suppressed or prevented without substantial modification of the desirable properties of such oils and aqueous emulsions thereof by incorporating in them a small amount of a branched-chain aliphatic amine containing from 16 to 32 carbon atoms. We have found that an oil or oil composition containing a branched-chain aliphatic amine containing 16 to 32 carbon atoms is markedly resistant to foaming even under the most violent conditions encountered in commercial practice. The presence of the branched-chain aliphatic amine apparently causes the film of the oil foam to rupture thereby quickly destroying the foam. In fact, particularly when an adequate amount of the branchedchain aliphatic amine is used, its presence so rapidly breaks the oil foam that substantially all foam is destroyed as fast as it is formed.

The branched-chain aliphatic amines contemplated for use according to this invention include primary, secondary and tertiary amines, wherein the compounds contain a total of 16 to 32 carbon atoms. Thus, the hydrocarbon radical in a primary amine can contain from 16 to 32 carbon atoms. In the case of a secondary amine wherein the hydrocarbon radicals contain the same number of carbon atoms, each of the hydrocarbon radicals can contain from 8 to 16 carbon atoms. In the case of a tertiary amine wherein the hydrocarbon radicals contain the same number of carbon atoms, each of the hydrocarbon radicals can contain from 6 to 10 carbon atoms. Exemplary of the branched-chain primary amines which may be used are hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, eicosyl' amine, heneicosylamine, tetracosylamine, hexacosylamine, octacosylamine, inelissylamine and laccerylamine. The branched-chain secondary amines include dioctylamine, dinonylamine, didodecylamine, ditetradecylamine and dihexadecylamine. The branched-chain tertiary amines include trihexylamine, trioctylamine and tri(decyl)amine, 1o :i)s

The branched-chain aliphatic amines which we have found to be particularly advantageous in suppressing foaming of a mineral oil and an aqueous emulsion thereof are the branched-chain aliphatic amines obtained upon treating with ammonia either an Oxo octyl alcohol or a hexadecyl alcohol obtained by condensing two moles of an Oxo octyl alcohol. The Oxo process, as is known, involves the addition of carbon monoxide and hydrogen to an olefin in the presence of a cobalt catalyst to produce an aldehyde containing one carbon atom more than the starting olefin. Hydrogenation of the resultant aldehyde produces the corresponding alcohol. Thus, according to one such process where the olefinic feed is a mixture of heptene prepared by the condensation of mixed butenes with propylene, the Oxo alcohol product is predominantly a mixture of branched-chain primary octyl alcohols. These alcohols and the condensation products of such alcohols are the compounds which upon treating with ammonia produce particularly efiecn've anti-foam agents.

(1) 2RCH3CH OH RCHsCHsCIHCH OH-l-H O RCHsCHsOH-l-R'CFHCHzOH R'CHCHsCHCHtOH+H:O

CH: H:

The groups designated as R and R represent amyl and hexyl groups, respectively. The product obtained by ,either Equation 1 or 2 is one in which the 2 carbon atom contains two hydrocarbon radicals, onebeing a hexyl radical and the other being an octyl radical. It has been postulated that a possible mechanism for the reaction involves dehydrogenation of the alcohol to form the aldehyde which then undergoes aldol condensation. The reaction conditions, in general, include temperatures of from about 300 to 500 F. and pressures from atmospheric to 100 pounds per square inch. It is generally desirable to remove the water formed during the reaction as fast as it is formed in order to obtain desirably high yields. The catalysts used in the reaction include a condensation catalyst, such as an alcoholate of an alkali metal of alkaline earth metal and a dehydrogenation catalyst, such as nickel, cobalt or iron preferably in a reduced state. In general, the catalyst is used in an amount from 1 to 15 percent by weight based on the alcohol treated.

The branched-chain aliphatic amines can be prepared according to various methods not constituting a part of this invention. One method by which these amines can be obtained is disclosed in application Serial No. 587,458, by Arthur C. Whitaker, filed May 28, 1956. Briefly, the process comprises introducing ammonia gas below the surface of the alcohol in the liquid phase in the presence of a hydrogenation-dehydrogenation catalyst at an elevated temperature and continuously removing water formed during the reaction. Effective hydrogenationdehydrogenation catalysts which can be used in catalyzing the reaction include Raney nickel, nickel on alumina, platinum, chromia on alumina of molybdenum oxide on alumina. The concentration of the catalyst preferably comprises about 3 to about parts by weight per 100 parts by weight of alcohol. The reaction is preferably carried out at atmospheric pressure although pressures up to about 100 pounds per square inch can be employed. The reaction is carried out at a temperature of about 150 to about 250 C. The ratio of alcohol to ammonia is such that the alcohol is present in molar excess. In general, at least about 1.1 mols of alcohol, preferably about 1.3 to about 3 mole of alcohol, per mol of ammonia is employed.

The branched-chain aliphatic amines which we can use can be either pure products or commercial mixtures predominating in a particular branched-chain aliphatic amine containing small amounts of associated materials present in the production of the branched-chain aliphatic amines. In the preparation of trioctylamine, for example, the resultant product may contain a small amout of a hydroxy derivative thereof such as dioctylhydroxyoctylamine.

In preparing our improved oil compositions, .the branched-chain aliphatic amine may be incorporated in the oil or oil composition directly by any suitable method. It is sometimes advantageous first to incorporate the branched-chain aliphatic amine in part of the oil to form a concentrate and then add this concentrate to the remainder of the oil. Standardized concentrates can be needed. In such case, the desired amount of standardized concentrate is added to the oil composition and the mixture is agitated until uniform. Such standardized concentrates are themselves valuable anti-foam compositions. For instance, when added to oil or oil compositions which have foamed, they readily destroy the foam present and stop further foaming. In such cases, they can be quickly blended with oils, oil compositions and crude oil and uniformly incorporated therein before serious foaming occurs.

The amount of branched-chain aliphatic amine required in accordance with the invention will vary with the tendency of the oil itself to foam and with the severity of the conditions to which the oil is subjected. In general, the amount is in the order of 0.05 to l percent by weight based on the weight of the lubricating composition. In some instances, where the oil itself does not foam excessively in the beginning, the aliphatic amine can be used effectively in amounts of about 0.001 percent. A convenient method of adding small amounts of the aliphatic amine to the oil, as noted above, comprises the use of a concentrate. Thus, to add 0.001 percent of trioctylamine to the final oil would require the addition of 0.1 percent of a concentrate containing 1.0 percent of trioctylamine. Other concentrates can be prepared containing from 1 to 10 percent by weight and more of the aliphatic amine. Thus, valuable anti-foam concentrates are prepared by dissolving in a hydrocarbon liquid from 1 to 10 percent by weight of a branchedchain aliphatic amine containing from 16 to 32 carbon atoms. By way of illustration, valuable concentrates comprise a hydrocarbon liquid containing from about 1 to about 10 percent by weight of an amine such as a branched-chain hexadecylamine, dihexadecylamine or trioctylamine. By adding from 0.1 to 10 percent by weight of such concentrates to mineral lubricating oils or oil compositions, improved lubricants having marked resistance to foaming are readily and easily obtained.

This invention is efiective in suppressing and preventing foaming in oils and oil compositions generally. The invention is particularly advantageous, however, in connection with mineral oils and aqueous emulsions thereof and is therefore described hereinafter more in detail in connection with its use in suppressing and preventing foaming in such compositions.

While this invention is primarily concerned with suppressing foarning in the heavier oils, the branched-chain aliphatic amines are also effective in reducing the foaming of lighter oils, such as those used in steam turbines. Trioctylamine, for example, when used in light oils for anti-foam purposes does not deleteriously affect the emulsification characteristics of such oils. Thus, it is particularly desirable when the oils are used in lubricating steam turbines.

A particularly advantageous field of use for the oil compositions of the invention containing a branchedchain aliphatic amine is in oils which are used in preparng aqueous cuttng emulsions. Aqueous cutting emulsions are frequently circulated to the working surface of the metal either by a flooding technique or in the form of a thin. high speed jet. By either of these methods. a considerable amount of air is introduced into the emulsion. When the emulsion is circulated in the system the air tends to cause the emulsion to foam. Such foaming interferes with efiective lubrication of the metal cutting operation and also with the efficient removal of heat evolved in the operation. The foaming thus gives rise to short tool life and rough cutting. By the present invention, foaming of aqueous cutting oil emulsions and the accompanying disadvantages thereof are efiectively prevented and overcome.

The lubricating oil of the invention can contain detergents and/or other additive" agents including oiliness and extreme pressure agents, such as aromatic chlorine compounds, stabilized chlorinated paraflins, sulfurized fatty oils, and high molecular weight ketones and esters; viscosity index improvers, such as the high molecular weight polymers of isobutylene and the polymers of methacrylic esters; pour point depressants such as a condensation product of chlorinated wax and naphthalene and a condensation product of chlorinated wax and phenol followed by further condensation of this reaction product with organic acids; an anti-rust agent such as the cocoamine salt of a dialkyl orthophosphoric acid; and corrosion and oxidation inhibitors, such as 2,6-ditertiary-butyl- 4 methylphenol, trlphenylphosphite, tributylphosphite, beta naphthol and phenyl beta naphthylamine. In addition to these additive agents the lubricating oil may contain suitable oil-in-water emulsifying agents when the oil is to be used in producing a soluble cutting oil. Suitable oil-in-water emulsifying agents include oil-soluble sulfonates such as the mahogany sulfonates formed in the sulfonation of petroleum oils. They are ordinarily prepared as alkali metal sulfonates, for example, as sodium mahogany sulfonates. Other conventional oil-inwater emulsifying agents can be used including a sulfonated fatty material such as sulfonatcd sperm oil, olive oil, cottonseed oil, etc. Other suitable emulsifying agents are the stearates and oleates of alkylolamines such as mono-, di-, or triethanol amines and non-ionic complex esters and: as polyoxyethylene sorbitan fatty acid esters;

The relative amounts of the various additive agents to be used in the compositions of the present invention will vary depending upon the use to which the final composition is put- In any event the particular additive is employed in an amount sufiicient to produce the desired result. When a soluble cutting. oil is produced the emulsifying agent will comprise from about 15 to 40 percent by weight of the soluble oil composition. While easily emulsifiable oils may contain as little as 5 percent by weight of the emulsifying agent the oils which are emulsified only with difliculty may require as much as 50 weight percent emulsifying agent. For most cutting operations the cutting liquid contains at least about 5 percent by volume of the soluble oil with amounts in the order of 15 to 20 percent by volume being preferred. The soluble cutting oil may also contain resin acid soap and one or more coupling agents such as diethylene glycol and butyl Carbitol.

The effectiveness of the branched-chain aliphatic amines in preventing foaming in mineral oils and aqueous emulsions thereof may be demonstrated by means of ASTM test designation D892-46T in which the oil is controllably aerated under fixed conditions so that the results obtained in a series of tests are directly comparable.

The trioctylamine used in illustrating the present invention was prepared from isooctyl alcohol obtained from the 0x0 process and ammonia according to the following procedure. A mixture containing 200 grams of isooct'yl alcohol and grams of Raney nickel were placed in a reaction vessel. About 20 grams of ammonia were bubbled through the mixture at a reaction temperature of about 165 to 190 C. over a period of about three and a half hours. The water vapor which formed during the reaction was condensed and removed from the reaction zone substantially as fast as it was formed. The conversion of the alcohol was substantially complete, and about 170 grams of product were recovered. The product so recovered consisted predominantly of a mixture of trioctylamines containing a small amount of dioctylamine and dioctylhydroxyoctylamine. This product was then distilled at a pressure of 20 millimeters of mercury. The fraction boiling between 215 and 224 0., consisting essentially of a mixture of isomeric trioctylamines, was separately recovered for use in illustrating the present invention. The octyl groups attached to the nitrogen atom are branched-chain groups typical of those 6 obtained by the Oxo process. The trioctylamine thus obtained had the following properties:

Gravity, 'API 41.2.

Specific gravity, 60/60 F- 0.8193. Viscosity, kinematic, cs.:

At 100 F 9.14.

At 210 F 2.36. Flash point, ASTM D-92 325 F. Color Water white. Odor Bland.

Refractive index, n 20/D--..- 1.4512. Neutralization value, ASTM D-664 159. Boiling range:

At 20 mm. Hg 215 to 224 C. At 760 mm. Hg 343 to 358 C. Solubility Insoluble in water, soluble in organic solvents.

In preparing the samples for the foam test, the trioctylamine mixture was added directly to the lubricating composition. Thus, in the case of the SAE 50 oil, the trioctylamine was added to and thoroughly admixed with the oil. In the case of the soluble cutting oil an emulsion was prepared by adding 20 parts by volume of soluble oil to parts by volume of tap water. The trioctylamine was added to and admixed with the emulsion thus formed. We have found that if the trioctylamine is added to the soluble oil before forming the emulsion there is a marked decrease in the emulsifiability of the oil.

The mineral lubricating oil was a highly refined paraffinic mineral lubricating oil of SAE 50 grade having an API gravity of 27.2; a viscosity of 1156 SUS at 100 F. and 99 at 210 F.; a viscosity index of 101; a flash point (O.C.) of 550 F.; a fire point (O.C.-) of 625 F., and a pour point of 0 F. The soluble or emulsifiable cutting oil used to prepare the aqueous cutting oil emulsion consisted of about percent by weight of a /2 Texas oil, about 0.1 percent of butyl Carbitol, 0.5 percent water, 10.5 percent sodium sulfouate, 0.4 percent diethylcne glycol and 3.5 percent potassium soap of wood rosin. The soluble cutting oil has an API gravity of 21.5; a viscosity of 200 SUS at 100 F. and 43.6 SUS at 210 F.; a flash point (0.0) of 320 F.; a fire point (O.C.) of 350 F. and a pour point of 20 F.

The data summarized in Table I will illustrate by means of the above-designated ASTM test the advantageous results obtained by incorporating trioctylamine in a mineral lubricating oil and an aqueous cutting oil emulsion at 75 F.

As shown by the data summarized in Table I, the addition of trioctylamine to the mineral lubricating oil and the cutting emulsion improved their respective foaming characteristics: at 75 F. When the SAE 50 mineral oil was further tested at 200 F., ml. of foam formed in 5 minutes. When the same mineral oil containing 1.0 percent of trioctylamine was tested at 200 F., only 65 ml. of foam formed in 5 minutes.

branched-chain primary amine and a branched-chain seclowed in preparing thelubricating compositions contain-' ing the branched-chain tertiary amine, i.e., trioctylamine. The hexadecylamine and the dihexadecylamine can be prepared by various procedures including bubbling ammonia through a liquid branched-chain hexadecyl alcohol or a liquid mixture of the isomeric branched-chain hexadecyi alcohols by. a procedure similar to that used in making the trioctyl amine. In this instance, however, hexadecyl alcohol is used instead of isooctyl alcohol. The hexadecyl alcohol is a branched-chain alcohol or probably a mixture of isomeric branched-chain C alcohols which in obtained upon condensing 2 moles of isooctyl alcohol or an isomeric alcohol mixture by the Guerbet reaction, the isooctyl alcohol being first obtained according to the x0 process. The hexadecylamine and the dihexadecylamine which we used in illustrating the invention had the following properties:

The data summarized in Table II will illustrate by means of the ASTM test designated hereinabove, the ad vantageous results obtained by incorporating hexadecylamine and dihexadecylamine in a mineral lubricating oil and an aqueous cutting oil emulsion at 75 F.

Table II Foaming Tend- Foam Sta.-

ency billty FoamVolume, Foam Volume, ml., at end of m1., at end of 5min. blowing iii-min. settling period period SAEBOBaseOil 320 0in4.5min. SAE 0 Base Oil plus 1.0% hem decylamine 210 01:12.5 min. SAE 50 Base Oil plus 0.1% how eoylamine 80 01111.5 min. SAE 50 Base Oil plus 1.0% dihexaecylamine 130 0in1.75 min. SAE 50 Base 011 plus 0.1% dihexrv deoylamlne 90 0in2min. Cuttin emulsion containing 20% solubeoil 440 290. Cuttin emulsion mntaining 20% solube oil plus 1.0% hexadecyiamine 250 15. Cutting emulsion containing 20% soluble oil plus 0.1% hexadecyb amine 1B0 15. Cuttin emulsion containing 20% solube 011 plus 1.0% dlhexadeeylamine 115 15. Cuttin emulsion containing 20% solube oil plus 0.1% dihexadecylamlne 235 m.

As shown by the data summarized in Table II the addition of 0.1 to 1.0 percent of hexadecylamine and dihexadecylamine to the mineral oil and the cutting oil emulsion improved their respective foaming characteristics at 75 F. When the SAE 50 mineral oil was further tested at 200 F., 100 milliliters of foam formed in five minutes. When the same mineral oil containing 1.0 only and milliliters of foam formed respectively in and 0.1 percent of hexadecylamine was tested at 200 F. five minutes. Under the same conditions using 1.0 and 0.1 percent of dihexadecylamine, the amount of foam formedin five minutes was further reduced to 15 and 50 milliliters, respectively.

While our invention has been described above with reference to various specific examples and embodiments, it will be understood that the invention is not limited to such illustrated examples and embodiments and may be variously practiced within the scope of the claims herein made.

We claim:

1. An aqueous cutting oil emulsion of reduced foaming properties comprising a major amount of water. about 5 to about 20 percent by volume of an emulsifiable cutting oil comprising from about 50 to about percent by weight of a mineral lubricating oil and from about 5 to about 50 percent by weight of emulsifying agent, and about 0.001 to about 1.0 percent by weight of a branched-chain trioctylamine.

2. An aqueous cutting oil emulsion of reduced foaming properties comprising a major amount of water, about 5 to about 20 percent by volume of an emulsifiable cutting oil comprising from about 50 to about 95 percent by weight a mineral lubricating oil and from about 5 to about 50 percent by weight of an oil-soluble sulfonate emulsifying agent, and about 0.001 to about 1.0 percent by weight of a branched-chain trioctylamine.

3. An aqueous oil emulsion of reduced foaming properties comprising a major amount of water, at least about 5 percent by volume of an emuisifiable oil comprising from about 50 to about 95 percent by weight ofa mineral lubricating oil and from about 5 to about 50 percent by weight of emulsifying agent, and about 0.001 to about 1.0 percent by weight of a branched-chain trioctylamine.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,614 Denman Ian. 13, 1953 2,304,805 Denman Dec. 15, 1942 2,363,923 Denman Nov. 28, 1944 2,758,086 Stuart et al. Aug. 7, 1956 2,832,741 Gottshali et al Apr. 29, 1958 FOREIGN PATENTS 733,783 Great Britain Iuly 20, 1955 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent, No 2376 240 March 21 1961'" H William 1. Gilbert et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 35, for "prepared read proposed column 3 lines 33 and 49 for -;"-of",; each occurrence, read or column 4, line 61, for "E-parng aqueous. cuttng" read paring aqueous cutting column 7, line 17', for "in" read is column 8 line 8 strike out .:".only O -and 7O milliliters of foam formed respectively in" and insert the same after "200 Ff" in line 9 same column; line 33, after -"weight" insert of "a Signed and sealed this 15th day of August 1961. (SEAL) Y Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

3. AN AQUEOUS OIL EMULSION OF REDUCED FOAMING PROPERTIES COMPRISING A MAJOR AMOUNT OF WATER, AT LEAST ABOUT 5 PERCENT BY VOLUME OF AN EMULSIFIABLE OIL COMPRISING FROM ABOUT 50 TO ABOUT 95 PERCENT BY WEIGHT OF A MINERAL LUBROCATING OIL AND FROM ABOUT 5 TO ABOUT 50 PERCENT BY WEIGHT OF EMULSIFYING AGENT, AND ABOUT 0.001 TO ABOUT 1.0 PERCENT BY WEIGHT OF A BRANCHED-CHAIN TRIOCYTLAMINE. 